﻿using System;
using System.Globalization;
using System.Windows;
using System.Windows.Data;
using System.Windows.Markup;

namespace MugenMvvmToolkit.Converters
{
    /// <summary>
    ///     This converts a Boolean to a Visibility.  It supports mapping the conversions.
    /// </summary>
#if WPF
    [ValueConversion(typeof(bool), typeof(Visibility))]
    [MarkupExtensionReturnType(typeof(BooleanToVisibilityConverter))]
#endif
    public class NullToVisibilityConverter :
#if !NOMARKUPEXT
 MarkupExtension,
#endif
 IValueConverter
    {
        #region Constructors

        /// <summary>
        ///     Initializes a new instance of the <see cref="NullToVisibilityConverter" /> class.
        /// </summary>
        public NullToVisibilityConverter()
        {
            NotNullValue = Visibility.Visible;
            NullValue = Visibility.Collapsed;
        }

        #endregion

        #region Properties

        /// <summary>
        ///     Mapping for False to Visibility.  Defaults is Collapsed.
        /// </summary>
        public Visibility NotNullValue { get; set; }

        /// <summary>
        ///     Mapping for null to Visibility.  Defaults is Collapsed.
        /// </summary>
        public Visibility NullValue { get; set; }

        #endregion

        #region Implementation of IValueConverter

        /// <summary>
        ///     Converts a value.
        /// </summary>
        /// <returns>
        ///     A converted value. If the method returns null, the valid null value is used.
        /// </returns>
        /// <param name="value">
        ///     The value produced by the binding source.
        /// </param>
        /// <param name="targetType">
        ///     The type of the binding target property.
        /// </param>
        /// <param name="parameter">
        ///     The converter parameter to use.
        /// </param>
        /// <param name="culture">
        ///     The culture to use in the converter.
        /// </param>
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            Should.BeOfType(targetType, "targetType", typeof(Visibility));
            if (value == null)
                return NullValue;
            return NotNullValue;
        }

        /// <summary>
        ///     Converts a value.
        /// </summary>
        /// <returns>
        ///     A converted value. If the method returns null, the valid null value is used.
        /// </returns>
        /// <param name="value">
        ///     The value that is produced by the binding target.
        /// </param>
        /// <param name="targetType">
        ///     The type to convert to.
        /// </param>
        /// <param name="parameter">
        ///     The converter parameter to use.
        /// </param>
        /// <param name="culture">
        ///     The culture to use in the converter.
        /// </param>
        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            Should.MethodBeSupported(false, "NullToVisibilityConverter.ConvertBack()");
            return null;
        }

        #endregion

#if !NOMARKUPEXT
        #region Overrides of MarkupExtension

        /// <summary>
        ///     When implemented in a derived class, returns an object that is set as the value of the target property for this markup extension.
        /// </summary>
        /// <returns>
        ///     The object value to set on the property where the extension is applied.
        /// </returns>
        /// <param name="serviceProvider">
        ///     Object that can provide services for the markup extension.
        /// </param>
        public override object ProvideValue(IServiceProvider serviceProvider)
        {
            return new NullToVisibilityConverter { NullValue = NullValue, NotNullValue = NotNullValue };
        }

        #endregion
#endif
    }
}
